...and the car bucks slightly. Replaced the O2 sensor first thing...no change. When I am cruising the car reads retardedly low O2 numbers but, when I get into boost at all there is a slight pop that I can feel in the pedal(backfire in the intake?) and then the O2's come back and the car feels fine WHILE IN BOOST ONLY. I have not gone higher than ~5psi since this stared for fear of something bad happening. Checked fuel pressure... it's fine. The motor has ~4000 miles on it 30 over with 204-214 cam(has been running like a champion). I'm thinkin' coil pack or ign. module? any ideas?